Hi Jeanne, I've always wondered about these myself. They come in a variety of shapes and colours. Posibilities include Murano, Czech, Canadian or Far East. I've seen many of these, but never one with a label. A pic of the base may help someone to identify them, but I have a feeling we will never know for certain who made these.
Oh and a bit of useless info - these amber ones usually contain something called "Selenium", which makes the glass glow bright orange in UV light.